3D Printer Filament Basics

Most current 3D printers feed the plastic into the printer in the form of filament, sort of like the string in the head of a weed wacker.

Diameter

Filament comes in two standard diameters, 1.75 mm and 3.0 mm. The 3.0 mm filament is the older standard and is slowly being upstaged by the 1.75 mm because it can be pushed slightly more easily, controlled a little better and sometimes leaves fewer tails hanging off the sides of your object.

The part of your printer that pushes the plastic filament is called the extruder. Most printers and extruders work with just one diameter. You will want to be sure to learn what your printer needs so you can get the right size.

Some printers will use a proprietary diameter filament. We suggest that you research this before buying a printer. You may want to use the standard filament that is more readily available. You will probably also have more colors to choose from and at a competitive price.

Variations in Diameter

Filament, even standard filament, will vary in diameter. You may find variations in diameter from the same manufacturer. One color filament may be a slightly different diameter than another. This is to be expected. The 1.75 mm or 3.0 mm definition is actually the maximum size of the filament, not the defined size.

Lumps and Neck-Downs

It sometimes happens that a filament will get thinner or fatter at certain places. This happens when something in the filament extrusion process is changed. It could be a difference in the raw plastic stock or an electrical power disruption. Good manufacturers will rarely sell plastic with these issues as it can either get stuck in your printer or cause the extruder to lose its grip and strip the plastic or even rip it in two.

If you notice something in your filament during a print, it is sometimes possible to cut the offending piece away and glue the two ends together. Believe it or not, acetone works great as a glue for ABS filament.